It is well known, in the art of luminescence detection and measurement, that certain substances undergo a chemical reaction which results in the emission of luminescence or light from those substances. This phenomenon is the basis for analysis in clinical and research laboratories.
For example, the detection and measurement of luminescence forms the basis for such processes as luminescence innumo assay (LIA), in that bioluminescent and chemiluminescent reactions are utilized in such assays.
In such procedures, typically, the luminescent or light-emitting substances are deposited in a plurality of wells, and a detector having a fixed detector position is provided. In order to detect the light emitted from the chemically reactive substances in the wells, the array of wells is typically moved in accordance with a predetermined pattern so that each successive well is moved into the detection position. In this manner, detection data are obtained from each substance in each successive well.
Such a technique and arrangement are disclosed, for example, in U.S. Pat. No. 4,772,453--Lisenbee and U.S. Pat. No. 5,202,091--Lisenbee. However, there are problems and disadvantages associated with the arrangement described above and disclosed in the latter patents.
A primary disadvantage of arrangements of the prior art resides in the fact that, due to the bulky nature of the detection device and associated circuitry, the detector and its associated circuitry are maintained in a fixed detection position, and the plurality of wells in which the substances are contained is moved in accordance with a predetermined pattern of movement. This movement can result in disturbance of the substances contained in the wells and, in an extreme case, could result in spillage of those substances. In addition, such an arrangement of the prior art is necessarily inflexible in that the plurality of wells is moved in one, and only one, predetermined pattern of movement.
Furthermore, in such arrangements of the prior art, the detection device typically employed is a photomultiplier tube (PMT). In order to obtain satisfactory test results, an adjustable aperture is employed between the PMT and the plurality of wells. Moreover, it is necessary, during operation of such an arrangement of the prior art, to physically adjust the aperture size. Moreover, even if it is possible to electronically control or adjust the size of the aperture associated with the PMT, such adjustment is relatively slow and unreliable in that physical movement of the aperture is necessary.
Therefore, there is a need in the prior art for a device and method for detection of light emitted by chemically reactive substances held in a plurality of wells, wherein the detector and its associated circuitry are moved relative to the wells, rather than vice-versa. In addition, there is a need in the prior art for the development of a device and method for detection of light emitted by chemically reactive substances, wherein the slow and relatively less reliable technique of adjusting the size of the aperture associated with a PMT detector is replaced by a quicker and more reliable technique.
Other arrangements representative of the prior art are disclosed in the following U.S. Pat. Nos. 4,154,795; 4,501,970; 4,580,895; 4,755,055; 4,818,883; 5,082,628; 5,086,233; 5,139,745; 5,321,261; and 5,401,465.